3. Electronic Theses and Dissertations (ETDs) - All submissions

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Browsing 3. Electronic Theses and Dissertations (ETDs) - All submissions by SDG "SDG-15: Life on land"

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    Equitable access to mineral resources in the South African MPRDA: the case of artisanal and small scale mining
    (2019) Muponde, Tatenda Wayne
    Artisanal and Small Scale Mining (ASM) is a growing sector in the South African mining industry and yet it remains highly unregulated. The main mining regulatory tool in South Africa is the Minerals and Petroleum Resources Development Act (MPRDA) which has the promotion of equitable access to mineral resources as one of its main objectives. However, despite the objectives of the MPRDA, a lack of formal access into the mining industry plagues the ASM sector and still remains as one of the impediments to the growth of the sector. The lack of a proper regulation that provides for equitable access to mineral resources in the MPRDA creates a gap in our mining laws that can easily be exploited by ASM miners through informal mining. This paper argues that it is imperative for South African mineral law to include ASM miners and grant them proper access to minerals as this will be consistent with our Constitutional values of equality. It further argues that the inclusion of ASM into the regulatory framework will allow for greater accountability of the ASM sector especially in terms of its negative environmental footprint. Therefore, the paper seeks the inclusion of ASM into the South African mineral law regulatory framework through an amendment of the MPRDA by including a chapter specifically dealing with ASM. It is argued that the inclusion of ASM will not only be in line with the Constitutional values of equality but will also help in facilitating the advancement of the Constitutional environment right.
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    Petrography, geochemistry and mica mineral chemistry of granites and granophyres from the mutue fides-stavoren tin field, the Lebowa granite suite
    (2021) Ray, Michael Eden
    The Mutue Fides-Stavoren Tin Field in the Palaeoproterozoic Bushveld Complex, lies approximately 30 km northwest of Marble Hall in Mpumalanga. The lithologies comprise granites from the upper portions of the Lebowa Granite Suite, granophyres from the Rashoop Granophyre Suite and quartzites from the Pretoria Group of the Transvaal Supergroup. The granites are characterised by localised zones of endo- and exogranitic cassiterite mineralisation. Although these tin deposits have been mined, mainly artisanally since the early 1900s, there is limited data on the petrology and geochemistry of the granite suite of the area and no mineral chemistry. This study provides petrographic and geochemical data from samples of outcrop, half-core, and mine-dump material of the granites and granophyres and presents mica and chlorite mineral composition data for the first time from this area. Geochemically the granites can be distinguished from other granite facies of the Lebowa Granite Suite and a new name - the Gaasterland Granite - has been proposed for this granite facies. This distinction is most clearly shown by their LILE compositions (5-40ppm Sr, 350-770ppm Ba and 220-410ppm Rb) in contrast to the Nebo Granite (30-140ppm Sr, 500-2500ppm Ba and 125-250ppm Rb). The petrographic and geochemical evidence suggests that the granophyres, which are host to significant cassiterite mineralisation, formed as an early intrusive phase. This contrasts with previous interpretations that the granophyres formed either as a result of metamorphism of Transvaal sedimentary rocks during the intrusion of the underlying Rustenburg Layered Suite or as a late phase intrusion between the Lebowa Granite Suite and Transvaal sedimentary succession. A sequence of late-stage hydrothermal alteration processes was identified in the granites and granophyres. Early pervasive microclinisation of perthitic III feldspars was followed by minor albitisation in which a ‘snowball texture’ was developed. Subsequent greisenisation of the granite resulted in an assemblage of intensely sericitised alkali-feldspar, white mica, quartz and interstitial purple fluorite. Greisen halos around veins in the granophyre consist of dark green to honey brown mica, quartz, white and purple fluorite, topaz, chalcopyrite, pyrite and hematite. Cassiterite crystallised during the greisenisation and late silicification stages of alteration with a final stage of chloritisation. Mineral compositional data revealed there is a clear distinction between magmatic and hydrothermal mica compositions within the Lebowa Granite Suite. During differentiation magmatic mica evolved from an Fe-Ti-rich annite upwards through the granite sheet to hydrothermal phengite micas that are depleted in Fe and enriched in Al. A late stage hydrothermal annite-siderophyllite within the Stavoren Granophyre is highly depleted in TiO2 and enriched in Cl and FeO (38.0 - 41.0 wt%). Such evolved mica compositions within the roof portion of the Lebowa Granite Suite is indicative of hydrothermal alteration and tin mineralisation. Such mineralised sectors are limited in the Lebowa Granite Suite because the sheeted architecture of the intrusions limited the potential for concentration of hydrothermal fluids in apical portions thus restricting extensive rock-fluid interaction and consequent ore deposition.
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